The present invention relates to a process for the continuous catalytic preparation of ethylene glycol carbonate (EGC) from ethylene oxide (EOX) and carbon dioxide (CO.sub.2), which is characterised by a procedure which is adiabatic and particularly mild, energy-saving and material-saving.
Many proposals have been made regarding the preparation of EGC. These relate in the main to the use of certain catalysts. An extensive account of this is to be found in Fette, Seifen, Anstrichmittel 73, (1971), 396 ff. Adiabatic temperature conditions are described in this account as not being technically feasible (loc. cit. 398). In the process described there, CO.sub.2 and EOX are reacted together at 80 bar and 190 to above 200.degree. C. in a reactor filled with ethylene glycol carbonate, and the heat of reaction is conducted away with the aid of a heat carrier circulating in counter-current which itself is cooled using water. Under these reaction conditions, peak temperatures of up to 220.degree. C. in the reactor are obtained, which can be harmful to the product, which is expressly referred to in the cited publication (p. 397), and which would be difficult to overcome in particular in industrial large-scale plants. The overall energy of reaction is conducted away unutilised in this case. Adiabatic temperature conditions, in contrast to this, are characterised in that all of the heat of reaction evolved is taken up by the reaction mixture itself; in the case of exothermic reactions this leads to increase in the temperature of the reaction mixture.
It was desired to develop a process which on the one hand avoids harmful temperature peaks and on the other hand utilises the energy of reaction as far as possible, either in the novel process itself, for example to obtain EGC by distillation, or to generate heating steam for other processes.